Speeding up Microtubule Growth

Molecular biochemists doctor Gary Brouhard and doctor Jeff Stear (of The Stools) have teamed up to present their last couple years of work, published this week in Cell. CELL is perhaps the most prestigious journal in the world for publishing in the biosciences, and here they have pulled off the cover. Gary and Jeff have shown us how microtubule growth is mechanistically regulated on a molecular level, which until now has been the subject of debate, by the protein XMAP215.







Cover design by Gary Brouhard

The authors at their finest

In the authors' own words:

"Microtubules are long, slender filaments with which cellular structures such as the cytoskeleton, the mitotic spindle, and the axoneme are built. These structures are not static. Rather, they are broken down and rebuilt when a cell moves, changes shape, or progresses through the cell cycle. This remodeling is achieved by the disassembly and reassembly of microtubules and occurs primarily through the removal and addition of tubulin dimers at microtubule ends. "

(Here is a movie illustrating microtubules growing in live cells.)

More specifically:

"To distinguish among the different possible ways that XMAP215 might promote microtubule growth, we developed an assay to visualize single XMAP215 molecules during microtubule polymerization. We demonstrate that XMAP215 does not, in fact, act as a tubulin shuttle. Rather, XMAP215 acts as a processive polymerizing enzyme or polymerase: XMAP215 forms a 1:1 complex with tubulin and resides for long periods at microtubule plus ends where it catalyzes repeated rounds of addition of tubulin into the microtubule polymer."

Nice work, dudes.